1. Technical Field
The invention relates to the field of gas separation devices. More specifically, devices that use an electrochemical process to separate one gas (oxygen for example) from a mixture of gasses (air for example).
2. Background Art
In one embodiment of a gas generating system, a solid-state process is used to separate oxygen from atmospheric air for medical use. Such a device is called a ceramic oxygen generating system or COGS. The ceramic electrolyte used in the oxygen separation process must be maintained at a temperature of approximately 600Âxc2x0 C. or higher for the ionic transport mechanism to operate efficiently. In addition, a fairly uniform temperature distribution with the separation furnace is essential to proper and efficient system operation.
A significant problem arises when the product flow rate from the system is turned down. For any given operating temperature, the heat dissipated by the separation modules is roughly proportional to the square of the product flow rate while conductive heat losses through the furnace walls are essentially constant. An efficiently designed system is thermally balanced such that the heat dissipated by the modules is just slightly less than what is required to maintain the desired furnace temperature.
As product flow rate is reduced, the heat input to the system by way of the separation modules decreases very rapidly. Since the heat loss through the furnace wall remains unchanged, supplemental heat (supplied by of auxiliary heaters) will be needed in order to maintain the furnace at the desired operating temperature. This auxiliary heat input has no functional value, save for maintaining temperature, and a significant fraction of it bercomes an unrecoverable loss due to conduction through the furnace walls and other losses. Stated simply, a single furnace enclosure properly sized for one product flow rate can have an excessive, overhead, heat loss when that flow rate is reduced.
In addition, in a larger furnace as the input power to the modules is decreased and the input power to the auxiliary heaters is increased, temperature uniformity in furnace may be adversely affected. This is due, in part, to the very different surface characteristics and geometric shape factors between the separation modules and the auxiliary heaters. Reduced performance and possibly reduced system life may result from this lack of temperature uniformity.
While the above cited references introduce and disclose a number of noteworthy advances and technological improvements within the art, none completely fulfills the specific objectives achieved by this invention.
In accordance with the present invention, an oven insert for a gas generating system of the type that includes heating elements, heat exchanger, a gas generating module, an air inlet, and a product gas outlet, comprises a furnace enclosure member formed with a plurality of interior chambers. The interior chambers are adapted for holding at least one gas generating module. The interior chambers each have an opening formed an exterior face of the furnace enclosure member. The openings are uniformly separated along a central axis of the face of the furnace enclosure member.
The furnace enclosure member preferably includes embedded heater elements providing uniform heat distributed about the interior chambers.
These and other objects, advantages and features of this invention will be apparent from the following description taken with reference to the accompanying drawings, wherein is shown the preferred embodiments of the invention.